1. Field of the Invention
This invention relates to an integrated circuit package which includes power busses and signal connections formed on a two level tape structure used to provide connections to the integrated circuit die.
2. Description of the Related Art
In the packaging of integrated circuit structures, it is common to provide a metal tape assembly comprising a series of partially stamped out lead fingers usually attached together by a metal frame which is removed after the leads are connected to the integrated circuit die. Typical of such a lead frame tape assembly is the structure shown in Burns U.S. Pat. No. 4,413,404 which shows a number of metal foil leads fingers joined together by a central frame or ring which is then torn away after attachment of the die to the metal lead fingers.
Such metal lead assemblies are conventionally provided on a plastic dielectric tape which permits automation of the packaging process giving rise to the name or designation Tape Automated Bonding or TAB. Such a composite tape comprising a metal lead frame with a dielectric film backing material is shown in Angelucci et al U.S. Pat. No. 4,380,042 and Phy U.S. Pat. No. 4,380,566.
It is also known to provide an integrated circuit packaging means in the form of a printed circuit (PC) board structure comprising a PC board formed with a conventional printed circuit pattern on one side of a rigid dielectric material and a printed circuit pattern on the other side which includes a series of metal leads which extend over a cutaway portion of the dielectric material to facilitate electrical connection to an integrated circuit die mounted in the cutaway portion of the PC board structure. Such a structure is illustrated and described in Grossman et al U.S. Pat. No. 3,739,232.
As the size of integrated circuit structures shrinks, the space taken up on such dies with power busses as well as the possible added resistance imparted to the circuitry by attempts to shrink such power busses, it becomes more attractive to consider providing such power busses external to the integrated circuit die. It would be particularly desirable if such power bus circuitry could be made a part of the packaging without adding further structure to the package in the form of an external PC board or the like added to the package.